Multiple Beam Klystron with Doubly Convergent Electron Guns

78622S Existing Multiple Beam Klystrons are currently limited to electron guns with beams that do not converge toward the axis of the klystron. This limits the cathode emission current density, which in turn limits the output power or requires a larger device with overmoded cavities. As a consequence, high power RF sources for accelerators suffer reduced lifetimes and increased costs. This project will develop technology for converging the multiple beams toward the axis of high power klystrons, allowing use of fundamental mode cavities. The challenge will be to provide electron beams for efficient interaction with the RF circuit without beam spiraling or beam interception. Phase I will explore electrostatic and magnetic focusing techniques to allow convergence of the electron beams about their own axis and convergence of the ensemble of beams toward the axis of the RF source. A doubly-convergent multiple beam gun and an L-Band klystron that will be computationally designed. Commercial Applications and Other Benefits as described by the awardee: The doubly-convergent multiple beam gun technology should significantly extend the state of the art in high power, long life, RF sources, while simultaneously reducing cost and complexity. With higher power RF sources, the number required for large accelerator systems can be reduced, further reducing the cost.